1. Field of the Invention
The present invention relates to, among other things, a control device of a straddle-type vehicle, a transmission, and a straddle-type vehicle.
2. Description of the Related Art
The following description sets forth the inventor's knowledge of related art and problems therein and should not be construed as an admission of knowledge in the prior art.
Electronically-controlled transmissions having a transmission gear ratio or a transmission ratio (hereinafter referred to as “transmission ratio”) that can be controlled in a continuously variable manner (hereinafter referred to as “ECVT” (Electronically-controlled Continuously Variable Transmission)) are known. In an ECVT, the transmission ratio is automatically changed based on a transmission ratio map that indicates the relationship of the transmission ratio and a vehicle running state, such as, e.g., a vehicle speed, an engine speed, or a throttle opening degree. Accordingly, in a vehicle equipped with an ECVT (hereinafter referred to as “ECVT equipped vehicle”), there is no need for a rider speed change operation or clutch operation. As a result, presently, an ECVT is mounted in various types of vehicle.
However, in an ECVT equipped vehicle, the rider is not able to discretionarily change the transmission ratio to a transmission ratio other than that determined automatically in the transmission ratio map. In other words, other than the setting of the transmission ratio map, the transmission ratio cannot be discretionarily changed. Thus, it is comparatively problematic for the rider of an ECVT equipped vehicle to make active use of engine brake based on his/her intentions. More particularly, it is comparatively problematic for the rider to actively use stronger engine brake than that set by the transmission ratio map.
In addition, for example, in an ECVT equipped vehicle, it is also comparatively difficult for the rider to intentionally shift-down more than normal to increase vehicle acceleration, namely, perform a kick down operation, when the rider wishes to overtake another vehicle.
In light of the above circumstances, an ECVT equipped vehicle has been proposed that allows selection of either an AT mode in which the transmission ratio is automatically and continuously changed, or an MT mode in which the transmission ratio is manually changed by an operation of the rider. More specifically, for example, in Japanese Patent No. 2950957, an ECVT equipped vehicle is proposed in which the transmission ratio of the continuously variable transmission can be manually set in accordance with a position of a deceleration lever. Moreover, for example, in JP S62-175228, A, an ECVT equipped vehicle is proposed that is provided with a switch for forcibly changing the transmission ratio or manually performing shift-down.
In a known ECVT equipped vehicle in which it is possible to switch between the AT mode and the MT mode, in the AT mode, when the rider intentionally shifts down to accelerate or decelerate the vehicle, it is necessary for a complicated and troublesome operation to be performed. More particularly, in the AT mode, in order for the rider to intentionally shift-down to accelerate or decelerate the vehicle, it is necessary for the rider to perform operations at least three times, namely:
1. an operation for switching from the AT mode to the MT mode,
2. an operation for shifting down in the MT mode, and
3. an operation for switching from the MT mode to the AT mode.
Furthermore, when performing a shift-down operation in the MT mode, until the transmission ratio of the transmission becomes the most suitable transmission ratio, on some occasions, the rider himself/herself must operate the operation switch multiple times to adjust the transmission ratio. In other words, there is a problem, namely, the shift-down operation is complicated because the rider himself/herself must perform operations and adjustments related to the amount of the shift-down of the transmission ratio of the transmission.
Moreover, for example, even in the case of one type of MT mode, namely, even in an automatic MT mode in which the transmission ratio of the ECVT is automatically changed between a plurality of transmission ratios that are pre-set in a simulated, stepped manner, the problem of a complicated shift-down operation similarly occurs.
Also, even in the manual MT mode in which the transmission ratio of the ECVT is changed between the plurality of transmission ratios that are pre-set by operation of the rider, for example, when the rider wishes to shift-down a great amount, it is necessary for him/her to perform the shift-down operation multiple times. As a result, even in the case of the manual MT mode, similarly, the problem of a complicated shift-down operation for a suitable amount of shift-down sometimes occurs.
The description herein of advantages and disadvantages of various features, embodiments, methods, and apparatus disclosed in other publications is in no way intended to limit the present invention. For example, certain features of the preferred embodiments of the invention may be capable of overcoming certain disadvantages and/or providing certain advantages, such as, e.g., disadvantages and/or advantages discussed herein, while retaining some or all of the features, embodiments, methods, and apparatus disclosed therein.